Stimulation of various areas on the body is known to be an effective treatment method for various conditions that affect the body. These areas lie along certain channels or meridians according to the practice of acupuncture and are typically of small size, often referred to as acupuncture points on the body. Treatment typically consists of stimulation of a certain combination of these areas in a single therapeutic session. The combination and sequence of stimulation has been determined through thousands of years of acupuncture experimentation.
Stimulation can be done invasively using small needles that are manipulated once inserted into an acupuncture area (acupuncture), by applying electrical pulses to the invasive needles (electroacupuncture), or by applying a heated element to the invasive needles (moxibustion). For example, Bertolucci, Nausea Control Device, U.S. Pat. No. 4,981,146 (Jan. 1, 1991) describes a nausea control device in the form of a watch-like housing attachable to the human wrist by an adjustable attachment band. The device uses non-invasive nerve stimulation whereby electricity is passed through two electrodes to stimulate nerves located on the ventral side of the wrist (this anatomical position is sometimes referred to as the palmar side of the wrist). The treatment provided by the device is sometimes referred to as electro-acupuncture, which is a form of acupuncture. The ventral site of application is referred to in the acupuncture art as the P6 point, pericardium 6 point, or master point of the pericardium meridian (sometimes referred to as the vascular meridian).
Another method is to use noninvasive, localized pressure applied to the acupuncture area using a fingertip or a small, hard, typically rounded instrument (acupressure). Portable devices for acupressure stimulation of an acupuncture area have been proposed and some are available for use by the lay person. For example, the Sea-Band (Sea-Band UK Ltd., USA) acupressure device is used for treating nausea due to motion sickness and is comprised of an elastic band with an incorporated hard, plastic nodule that is placed over the P6 area. Similar devices with elastic or inelastic bands have been proposed for treating nausea and vomiting by stimulating acupuncture areas on the wrist, e.g., Giarratano, U.S. Pat. No. 5,078,728, Humphrey, U.S. Pat. No. D356,433, Bruckner et al., U.S. Pat. No. 5,695,520, Griffith, U.S. Pat. No. D274,557, Ferber, U.S. Pat. No. 5,709,647. Yoo (U.S. Pat. No. 5,774,424) describes an acupressure stimulator consisting of a pressure plate with nodules. The plate is attached to the back of a watch for stimulating the wrist area.
The acupressure methods described above deliver a constant level of pressure to the acupuncture site to be stimulated. The scientific literature indicates that this type of constant acupressure can be effective, but that the effect is not consistent and typically wanes over time. This is because of the well-known nerve response referred to as nerve accommodation, wherein the nerve accommodates to a constant stimulus and essentially ignores it. The action potentials necessary to achieve the effect are then no longer produced. Thus, the user may receive short-term benefit that wanes with time causing the undesirable symptoms to reappear.
Attempts have been made to circumvent this defect in constant pressure acupressure devices. Jacobs (U.S. Pat. No. 4,574,787) describes a liquid filled device wherein the fluid is caused to vibrate, the vibration causing a changing pressure. A separate vibration source is necessary and the liquid may leak. Strumor (U.S. Pat. No. 5,607,749) describes a similar system in which air is used as the fluid and movement causes differential pressure leading to air flow into certain protuberances causing them to exert variable pressure; movement is necessary to achieve the changing pressure so the user cannot be stationary. Fisher (U.S. Pat. No. 5,601,598) describes a method in which the user is required to periodically stretch a band to cause changing pressure. This requires the user to stop any activity to stretch the band. While these methods have some functionality, they suffer from needing bulky equipment or active user participation that severely limits their utility. Typical users of the anti-nausea wrist mounted acupressure range from sailors who might suffer motion sickness but require unhindered mobility to sedentary and ill patients desiring peaceful rest. These patients require extended periods of treatment, and the current devices are inconvenient and unworkable because they require constant operator action or immobility. For patients desiring extended treatment to be applied during normal activities and during rest, without operator attention, the devices described below are desired.